Center reference adjustable cutter holder for CNC lathe

ABSTRACT

A cutter holder for CNC lathe is disclosed to include a bottom holder block, which is affixed to the frame of a CNC lathe with screws and has a positioning groove with a middle semispherical recess for holding a barrel that holds a tool shank with a front chuck for holding a cutting tool, and a top holding down block, which is detachably affixed to the bottom holder block with screws to hold down the barrel and has a semispherical bottom recess fitting the spherical middle flank portion of the barrel corresponding to the middle semispherical recess of the bottom holder block.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a CNC lathe and more specifically, to acenter reference adjustable cutter holder for use in a CNC lathe.

2. Description of the Related Art

FIGS. 5 and 6 show a cutter holder 6 for a conventional CNC lathe. Asillustrated, the cutter holder 6 comprises a mounting hole 61, a barrel611 mounted in the mounting hole 61, and a tool shank 7 mounted in thebarrel 611. The tool shank 7 has a front chuck 71 adapted to hold acutting tool 8. The cutter holder 6 is fastened to the frame 4 of theCNC lathe with screws 612, enabling the cutting tool 8 to work on theworkpiece 9 at the workpiece chuck 5. According to this design, theparts of the cutter holder 6 are not adjustable relative to one another,therefore it is difficult to calibrate the position of the cutter holder6 relative to the workpiece chuck 5. The operator may be unable to findinaccurate position of the cutting tool 8 when working the workpiece 9,resulting in a poor processing quality or damage of the parts of themachine.

SUMMARY OF THE INVENTION

The present invention has been accomplished under the circumstances inview. It is therefore the main object of the present invention toprovide a center reference adjustable cutter holder for CNC lathe, whichenables the operator to calibrate the position of the cutting toolaccurately, achieving a high quality cutting work. To achieve this andother objects of the present invention, the cutter holder comprises abottom holder block, a holding down block, and a barrel. The bottomholder block comprises a top wall, a positioning groove formed in thetop wall and extending through front and rear sides thereof, a pluralityof mounting through holes disposed at two sides relative to thepositioning groove and fastened to a frame at a CNC lathe with screws, aplurality of screw holes symmetrically disposed at two sides relative tothe positioning groove, and a semispherical recess formed in the topwall on a middle part of the positioning groove. The barrel fits thepositioning groove of the bottom holder block, having a spherical middleflank portion fitting the semispherical recess of the bottom holderblock, and a center hole extending through two distal ends thereof forholding a tool shank. The holding down block is adapted to hold down thebarrel in the positioning groove of the bottom holder block, having asemispherical bottom recess fitting the spherical middle flank portionof the barrel and a plurality of mounting through holes disposed at twosides of the semispherical bottom recess and respectively fastened tothe screw holes of the bottom holder block with a respective screw.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an exploded view of a center reference adjustable cutterholder according to the present invention.

FIG. 2 is a sectional assembly view of the center reference adjustablecutter holder according to the present invention.

FIG. 3 corresponds to FIG. 2, showing the center reference of the cutterholder adjusted.

FIG. 4 is a schematic drawing showing the calibration of the position ofthe barrel in the tool holder with the use of a calibration rod.

FIG. 5 is a perspective view of a cutter holder according to the priorart.

FIG. 6 shows an use of the cutter holder according to the prior art.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring to FIGS. 1˜3, a cutter holder 1 for CNC lathe in accordancewith the present invention is shown comprising a bottom holder block 11,a top holding down block 16, and a barrel 19. The barrel 19 has aspherical middle flank portion 191 and a center hole 192 extendingthrough the two ends thereof. The bottom holder block 11 has apositioning groove 12 formed in the top wall and extending through thefront and rear sides for accommodating the barrel 19, a semisphericaltop recess 13 formed in the top wall on the middle of the positioninggroove 12 corresponding to the spherical middle flank portion 191 of thebarrel 19. The top holding down block 16 has a semispherical bottomrecess 17 corresponding to the semispherical top recess 13 of the bottomholder block 11. The bottom holder block 11 further has a plurality ofmounting through holes 14 and two screw holes 15 respectivelysymmetrically disposed at two sides relative to the positioning groove12. Screws 141 are respectively mounted in the mounting through holes 14and threaded into a locating frame 4 at a CNC lathe to affix the bottomholder block 11 to the locating frame 4. A tool shank 2 is mounted inthe center hole 192 of the barrel 19, having a front chuck 21 that holdsa cutting tool 3. The top holding down block 16 is covered on the bottomholder block 11 to hold the barrel 19 in the positioning groove 12,having two mounting through holes 18 respectively connected to the screwholes 15 of the bottom holder block 11 by a respective screw 181.

Referring to FIG. 4 and FIGS. 1˜3 again, after the cutter holder 1 hasbeen installed in the locating frame 4 of the CNC lathe, a calibrationrod 51 is fastened to the front chuck 21 of the tool shank 2, and thenthe two screws 181 are loosened, and then the other end of thecalibration rod 51 is inserted into the center of the workpiece chuck 5and firmly secured to the workpiece chuck 5, and then the barrel 19 ismoved in the positioning groove 12 to calibrate the position of the toolshank 2, keeping the center reference of the front chuck 21 in axialalignment with the center reference of the calibration rod 51, and thenthe two screws 181 are fastened tight to affix the top holding downblock 16 to the bottom holder block 11 and to hold down the barrel 19and the tool shank 2 in the calibrated position. At this time, thecalibration rod 51 can be removed from the workpiece chuck 5 andreplaced by the workpiece, and the cutting tool 3 can be fastened to thefront chuck 21 of the tool shank 2 for cutting the workpiece.

Although a particular embodiment of the invention has been described indetail for purposes of illustration, various modifications andenhancements may be made without departing from the spirit and scope ofthe invention.

1. A tool holder comprising: a bottom holder block, said bottom holderblock comprising a top wall, a positioning groove formed in said topwall and extending through front and rear sides thereof, a plurality ofmounting through holes disposed at two sides relative to saidpositioning groove and fastened to a frame at a CNC lathe with screws, aplurality of screw holes symmetrically disposed at two sides relative tosaid positioning groove, and a semispherical recess formed in said topwall on a middle part of said positioning groove; a barrel fitting thepositioning groove of said bottom holder block, said barrel having aspherical middle flank portion fitting the semispherical recess of saidbottom holder block, and a center hole extending through two distal endsthereof for holding a tool shank; and a holding down block adapted tohold down said barrel in said positioning groove of said bottom holderblock, said holding down block having a semispherical bottom recessfitting the spherical middle flank portion of said barrel and aplurality of mounting through holes disposed at two sides of saidsemispherical bottom recess and respectively fastened to the screw holesof said bottom holder block with a respective screw.
 2. The tool holderas claimed in claim 1, wherein said tool shank comprises a front chuckadapted to hold a cutting tool.